This invention relates generally to blood specimen collection systems. More specifically, the present invention relates to a blood specimen collection system wherein a cylindrical support includes an ejector mechanism which helps to position a needle assembly during use, and conveniently removes and ejects the needle assembly from the cylindrical support for disposal thereof following use.
Many types of blood specimen collecting systems are well known in the art. Currently, hospital and clinical practice require that blood specimens be taken simply, quickly, and with inexpensive and readily disposable equipment. Hypodermic syringes and needles have been satisfactorily used for this purpose for a number of years. It has been found, however, that ordinary hypodermic syringes and needles are less than desirable if blood is to be drawn from a patient for a number of separate tests.
More advanced blood specimen collecting systems have been developed which utilize a disposable needle and apparatus which permit blood to be received into one or more blood collection tubes without requiring that the needle be repeatedly inserted into the patient's vein. The collection tubes which initially receive the blood specimens are utilized to store the blood until the desired blood tests are performed.
Typical state-of-the-art blood specimen collecting systems utilize a standard disposable needle assembly which is placed into a threaded hole in an end wall of a hollow cylindrical support. The standard disposable needle assembly includes an externally extending hollow needle which is transcutaneously inserted into the patient's vein to draw blood, and another needle extending inwardly into the interior of the hollow cylindrical support. The two needles are coaxial and are in fluid communication with one another. Blood collection tubes utilized in such systems are sealed at one end with a breakable elastomeric septum. The collection tube is placed in the interior of the hollow cylindrical support so that the septum is pierced by the inwardly extending needle. The patient's blood is then drawn into the collection tube through the needles without coming into contact with the hollow cylinder.
When the desired amount of blood is received within the collection tube, it is withdrawn from the hollow cylindrical support and the breach through the elastomeric septum through which the inwardly extending needle passed, closes upon itself to seal the collected blood within the tube. Additional blood collection tubes can be inserted into the hollow cylindrical support for collecting additional specimens as described, without withdrawing the externally extending needle from the patient's vein. After the desired blood specimens have been obtained, the needle assembly is withdrawn from the patient and then discarded.
In order to remove the needle assembly from the hollow cylindrical support, it must be grasped and twisted to disengage from the threaded hole. For safety purposes, a protective cap or sheath is typically placed over the externally extending needle prior to attempting to unthread the needle assembly from the cylindrical support. Once the needle assembly is successfully removed from the cylindrical support, it is disposed of, usually by placing the needle assembly into a canister or container specially marked for receiving only such contaminated needles. Since the hollow cylindrical support does not come into contact with the patient's blood, the cylindrical support normally is not discarded after the blood specimen has been collected.
Although such state-of-the-art specimen collecting systems generally work well, they have the inherent disadvantage in that it is necessary to manipulate and touch the needle assembly after the needle has been in contact with the patient's blood. Such manipulation unfortunately gives rise to the possibility of accidently wounding or pricking of a health care worker. This problem arises especially in connection with the step of replacing a protective cap or sheath over the externally extending needle following the collection of blood and prior to disposal of the needle assembly. It is well known in the medical arts that certain serious, even fatal, diseases, such as Hepatitis and AIDS may be spread through accidental contact with infected blood. It is, therefore, imperative that health care workers exercise extreme care when utilizing such prior blood specimen collecting systems to insure that one is not accidentally pricked with a contaminated needle.
Accordingly, there has been a need for an improved blood specimen collecting system wherein exposure to contaminated needles is minimized or eliminated. Such an improved system should preferably permit the collection of blood samples in a manner similar to current state-of-the-art systems, provide for the use of standard blood collection tubes, and require only a minimum level of training of medical personnel to insure proper use thereof. Further, such an improved blood specimen collecting system should be of a simplified design which lends itself to economical manufacturing techniques. The present invention fulfills these needs and provides other related advantages.